Optimal sequences, power control, and user capacity of synchronous CDMA systems with linear MMSE multiuser receivers

摘要: There has been intense effort in the past decade to develop multiuser receiver structures which mitigate interference between users spread-spectrum systems. While much of this research is performed at physical layer, appropriate power control and choice signature sequences conjunction with receivers resulting network user capacity not well understood. In paper we will focus on a single cell consider both uplink downlink scenarios assume synchronous CDMA (S-CDMA) system. We characterize optimal linear (MMSE receiver). The system maximum number per unit processing gain admissible such that each its quality-of-service (QoS) requirement (expressed terms desired signal-to-interference ratio) met. This characterization allows one describe through simple effective bandwidth characterization: are allowed if only sum their bandwidths less than monotonic function QoS requirement. identify strategies so meet optimality sense minimizing allocated powers. It turns out allocation powers, MMSE just corresponding matched filter for user. also effect transmit constraints capacity.